t is smaller than ever before, they are guarding
Europa very closely. It is feared that they may have found and destroyed
our city there--an expedition is even now about to set out in a
desperate attempt to learn the fate of our fellows."

"Suppose the rays of the lifeboats were detected in landing?" asked
Brandon. "That might have given them a clue."

"Possibly; but it is equally possible that our own men became careless
in the operation of one of our own vessels. Having been unmolested so
long, they might have relaxed their vigilance. We may never know."

"Tell 'em to cancel the expedition--we'll shoot the visiray over
there right now and find out all about it. We'll let them know pretty
quickly. Also, you might tell them that you've got complete plans and
specifications for all the weapons that the hexans have, and a couple
besides, and that the quicker they shoot a ship out here after you, the
sooner they can get to building some stuff to blow those hexans clear
out of space!"

It was the work of only a few moments to drive the visiray projection
to Europa, where Czuv, to the great relief of all, found that the hexans
had not yet discovered either Wruszk or the Terrestrial workings.
All Europan humanity, fully aware of the hexan investment, was
exerting every possible precaution against discovery by the enemy.
This information was duly flashed to the Council of Callisto, and the
projection was then hurled across the intervening reaches of space and
into the cavern in which was being built the enormous rocket-ship in
which the Terrestrial refugees were to attempt the long voyage back
to their own distant planet.

It took some little time to convince Doctor Penfield that there had
been projected into the empty air of his little sanctum an absolutely
invisible and impalpable structure of pure force capable of receiving
and transmitting voice and vision. Once convinced of the reality of the
phenomenon, however, the speaker beside Brandon's communicator screen
fairly rattled under the fervor of his greeting, so great was his
pleasure at the arrival of the expedition of relief and in knowing that
King and Breckenridge, whom they had, of course, given up for dead, were
aboard the Interplanetary vessel.

Penfield reported that the work upon the great rocket-ship was
progressing satisfactorily, although slowly, since it was so much larger
than any vessel theretofore constructed by the Callistonians. Newton,
in turn, i